This application claims priority of French Patent Application No. 99 15009 filed Nov. 29, 1999.
The invention relates to elastic fibres and nonwovens for use in articles such as nappies, or baby diapers, sanitary towels, tampons or incontinence pads, bandages or in general for other similar articles used for hygienic purposes.
In numerous applications, nonwovens need some elasticity. In nappies, the fabric must stretch and contract in dependence on the normal movements of the child. A nappy without these elastic characteristics will restrict movement or leak. The elastic material should also be soft, easy to handle, and capable of breathing.
Elastomers used for elastic films often have an undesirable rubbery feel. When the substances are used in composite nonwovens, the user in contact with the fabric has a rubbery or sticky feeling which is undesirable for direct contact with the skin.
Elastic fabrics usually comprise elastic nonwovens or layers of elastic film. When elastic films are used and the fabric needs to breathe, it is conventional to make holes in the films. These holes may weaken the film and, when stretched, may constitute a site from where tears propagate in the film. Thin films are desirable economically but have limited strength, and this limitation is complicated by the presence of holes.
One method to meet the need for elasticity and for good contact with the skin, is to place a layer of fibrous nonwoven fabric on the elastic layer, producing a composite fabric having improved properties. The nonwoven fabric gives a surface covering the elstomeric layer and soft, capable of breathing and suitable for direct contact with the skin. The nonwoven layer also gives additional strength to composite materials. Solutions of this kind are described in U.S. Pat. Nos. 5,921,973, 5,853,881, 5,709,921, 5,681,645, 5,413,849 and 5,334,446.
The composite fabric has to be made in a number of operations with expensive equipment and raw material, including the elastic substances, nonwovens and adhesives.
WO 9425648 describes fibres having two constituents such as a core and sheath. The two constituents are preferably elastic.
The invention is concerned with fibres for obtaining a nonwoven without the need to produce a composite product or the resulting costs of operation and adhesives, while having the softness and feel required for contact with the skin and the elasticity required for the previously-mentioned hygienic articles.